Abstract

Montevecchio (SW-Sardinia) are presented. The statistic analysis of the relevés let to recognize 14 plant communities. The hygrophilous communities
have been ascribed to the class Phragmito-Magnocaricetea, the hemicryptophytic mesohygrophilous ones to Juncetea maritimi, the therophytic to
Tuberarietea guttatae and the hemicryptophytic mesoxerophilous to Lygeo-Stipetea.
The most interesting vegetation types turned out to be the chamaephytic and nanophanerophytic ones, both kinds are belonging to sardo-corsican
endemic alliances: Ptilostemono casabonae-Euphorbion cupanii and Teucrion mari, respectively. The first alliance comprises pebble vegetation with
distinctive ecological preferences, as they are able to colonize substrata polluted by heavy metal, with low pH values. Within this alliance, 4 new
associations have been recognized: Scrophularietum bicoloris, Dactylo hispanicae-Helichrysetum tyrrhenici, Mercurialido corsicae-Euphorbietum
cupanii and Dauco maritimi-Dittrichietum viscosae, the latter with two subassociations (typicum and rumicetosum glaucescentis). As to the Teucrion
mari, 1 new association and 1 subassociation have been described (Helichryso tyrrhenici-Genistetum sulcitanae and Stachydi glutinosae-Genistetum
corsicae euphorbietosum cupanii), found on aged mining dumps, where the long abandonment made possible the beginning of the pedogenetic
processes.
The present study let to reconstruct the vegetation dynamics, that in the mining areas are clearly differing from the surrounding territory. It was
possible to identify two special series, strictly related to these habitats and verging to the establishment of plant communities pertaining to the
climatophilous series: the first is developing on coarse, hard-sloping debris, with very low water retention; the second is developing on fine-grained
and coherent materials, found on flattened or gently-sloping sites, with high edaphic humidity. In wetlands, it was also possible to identify an
edaphohygrophilous series and a geoseries of endoreic water bodies, not exclusive of the mining habitats.